1. Field of the Invention
The present invention relates to a transistor and a manufacturing method of the same.
2. Description of the Related Art
In recent years, metal oxides having the characteristics of semiconductors (hereinafter, oxide semiconductors) have attracted attention. Metal oxides having the characteristics of semiconductors may be applied to a transistor (see Patent Documents 1 and 2).
There are many types of transistors. For example, transistors may be classified as a bottom gate-type structure and a top gate-type structure according to the positional relationship among a substrate, a gate, and a channel formation area. A transistor structure having a gate placed between a channel formation area and a substrate is called a bottom gate-type structure. A transistor structure having a channel formation area placed between a gate and a substrate is called a top gate-type structure.
In addition, transistors may be classified as a bottom contact type and a top contact type according to the connection position of a source and a drain with a semiconductor layer in which a channel is formed. A structure where the connection position of a source and a drain with a semiconductor layer in which a channel is formed is placed on a substrate side is called a bottom contact structure. A structure where the connection position of a source and a drain with a semiconductor layer in which a channel is formed is placed on a side opposite to a substrate is called a top contact structure.
Types of transistors are classified as a BGBC (bottom gate bottom contact) structure, a BGTC (bottom gate top contact) structure, a TGTC (top gate top contact) structure, and a TGBC (top gate bottom contact) structure.